Azido-alkyne click and oxysilane hybrid compositions

Abstract

The present invention provides alternative polyurethane composition comprising the reaction product of an azidated polyol and a poly(alkynyl carbamate) prepolymer, wherein the poly(alkynyl carbamate) prepolymer comprises the reaction product of a polyisocyanate, an alkynol, and an oxysilane. The reaction of the polyol and the prepolymer may occur in the presence of a catalyst or at a temperature of from 20° C. to 120° C. The inventive oxysilane and azido-alkyne hybrid click formulations provide comparable performance, and in some cases better performance, to / than urethane and azido-alkyne control click formulations in terms of pencil hardness, MEK double rubs, and glass transition temperature. The inventive alternative polyurethane compositions may be used to provide coatings, adhesives, sealants, films, elastomers, castings, and composites.

Description

FIELD OF THE INVENTION[0001]The present invention relates to alternative polyurethane compositions which are reaction products of a poly(alkynyl carbamate) and an azidated polyol. The azide and alkyne groups react in a 1,3-dipolar cycloaddition to form 1,4- and 1,5-disubstituted triazoles. At least one of the poly(alkynyl carbamate) and the azidated polyol contain —O(C═O)—NR— functional groups, wherein R=hydrogen or alkyl. The addition of an alkynol-oxysilane into the polyisocyanate chain results in alternative polyurethane compositions which may be thermally cured or may be cured with catalysts and are suitable for use as coatings, adhesives, sealants, films, elastomers, castings, and composites.BACKGROUND OF THE INVENTION[0002]“Click chemistry” is a term first used by Sharpless et al. (Angew. Chem. Int. Ed. 2001, 40, 2004-2021) to describe a family of synthetic reactions, which attempts to imitate nature by joining small molecules together with heteroatom links. Sharpless et al. s...

AI Technical Summary

Benefits of technology

The present invention provides new chemicals and methods for preparing them that can cure without using harmful isocyanates in the final step. This is done by using a reaction between an alkyne-functional resin and an azide-functional resin, which can occur at room temperature or with a little heat and in the presence or absence of a catalyst. This invention solves problems associated with the art by providing safer and more efficient methods for making polyurethane-based compositions.

Problems solved by technology

A significant disadvantage of the above-described reactions is the required use of di- and polyazides, which have relatively high nitrogen contents.

Such compounds are impracticable for industrial application due to the compounds' explosiveness.

The compounds of Tang et al. and Xin-Ming et al. have nitrogen contents in the form of azides of about 23% and 43%, respectively, which pose problems when the azide compounds are handled as such.